8VTM

Crystal structure of R. sphaeroides Photosynthetic Reaction Center variant Y(M210)2-bromophenylalanine

8VTM の概要

• エントリーDOI: 10.2210/pdb8vtm/pdb
• 分子名称: Reaction center protein H chain, CARDIOLIPIN, Reaction center protein L chain, ... (11 entities in total)
• 機能のキーワード: photosynthesis, membrane protein, electron transfer
• 由来する生物種: Cereibacter sphaeroides; 詳細
• タンパク質・核酸の鎖数: 3
• 化学式量合計: 99382.83

構造登録者

Tran, K.,Mathews, I.,Boxer, S.G. (登録日: 2024-01-26, 公開日: 2024-03-13, 最終更新日: 2025-09-24)

主引用文献

Tran, K.N.,Faries, K.M.,Magdaong, N.C.M.,Mathews, I.I.,Weaver, J.B.,Kirsh, J.M.,Holten, D.,Kirmaier, C.,Boxer, S.G.
Application of Amber Suppression To Study the Role of Tyr M210 in Electron Transfer in Rhodobacter sphaeroides Photosynthetic Reaction Centers.
J.Phys.Chem.B, 129:3317-3333, 2025

PubMed Abstract: The initial light-induced electron transfer (ET) steps in the bacterial photosynthetic reaction center (RC) have been extensively studied and provide a paradigm for connecting structure and function. Although RCs have local pseudo- symmetry, ET only occurs along the A branch of chromophores. Tyrosine M210 is a key symmetry-breaking residue adjacent to bacteriochlorophyll B that bridges the primary electron donor P and the bacteriopheophytin acceptor H. We used amber suppression to incorporate phenylalanine variants with different electron-withdrawing/-donating capabilities at the position M210. X-ray data generally reveal no appreciable structural changes due to the mutations. P* decay and PH formation are multiexponential (∼2 to 9, ∼10 to 60, and ∼100 to 300 ps) and temperature dependent. The 1020 nm transient-absorption band of PB is barely resolved for a few variants at 295 K and for none at 77 K. The results indicate a change from two-step ET for wild-type RCs to the dominance of one-step superexchange ET for the mutants. Resonance Stark spectroscopy reveals that the free energy of PB changes by -57 to +66 meV among the phenylalanine variants. Because PB apparently lies above P* in all phenylalanine variants, the perturbations primarily affect the energy denominator for superexchange mixing. The findings deepen insight into primary ET in the bacterial RC.

PubMed: 40134359
DOI: 10.1021/acs.jpcb.5c00082

実験手法

X-RAY DIFFRACTION (3.51 Å)